1. Field of the Invention
The present invention relates to a target substance detection system which has a detecting element where a metallic pattern is arranged on a substrate so as to detect trace of target substance in a sample using plasmon resonance, and a target substance detecting apparatus for measuring a capture amount of target substance to the detecting element. In particular, the present invention relates to a target substance detection system which has a detecting element which captures a target substance using a capturing body which recognizes a target substance specifically, and a target substance detecting apparatus which measures optically an amount of the target substance captured by the detecting element using a wide band of optical irradiation.
2. Description of the Related Art
Up to now, a measuring method of immobilizing metal nanoparticles on a substrate surface, and detecting a substance near the metal nanoparticles using localized surface plasmon resonance induced there is known. When light is incident into metal nanoparticles, such as gold and silver, a characteristic resonance spectrum appears by the localized surface plasmon resonance. Its resonance wavelength is dependent on a dielectric constant of a solvent near the metal nanoparticles. As the dielectric constant becomes large, absorbance of a resonance peak becomes large and is shifted to a long wavelength side.
In Nano Lett., Vol. 4, No. 6, 2004 1029-1034, construction of an element of aiming at enhancement in detection capability by giving a feature of triangular disk structure to a form itself of each silver particulate used for an element is exemplified.
In addition, a biosensor to which plasmon resonance is applicable is a measuring device using excellent biomolecule recognition ability which an organism and a biomolecule have, and is expected recently for broad applications to various analyses in not only a medical field but also environments, food stuffs, and the like.
Nevertheless, in order to draw out performance of a sensor element using plasmon resonance, it is necessary to catch sharply an optical change of the sensor element, that is, a change of an absorbance peak. A proposal of an optical system for that has not been known yet.